The present invention relates to a utility knife and more particularly to a utility knife which has a knife blade extending from its forward end.
In the past, utility knives have been assembled from two matching halves within which there is provided a knife blade. The two matching halves are adapted to interfit with each other to form the body of the tool and to be held together by any suitable means, such as screws. The two matching halves have spaces at their front ends in order to form an open mouth. Mounted within the matching halves of some utility knives is a blade carrier which is adapted to move forwardly in order to project the blade through the front open mouth to permit the tool to be used and to move backwardly to retract the blade within the two matching portions when the tool is no longer in use. In other utility knives presently in use, the blade is not retractable but is permanently held in either the extended position or the retracted position.
One of the problems in this type of a structure is that the front ends of the two matching portions which form the mouth tend to spread out when the tool is being used. This spreading action may not only prevent the tool from making an accurate cut, but, more importantly, may also allow the blade to be forced out of the front end of the tool to cause possible injury to the user.
Another problem with existing tools is the fact that the utility tool may not hold the blade firmly in place until the two halves are permanently secured together. This results in fluctuation of the two halves of the tool which can cause injury or prevent the knife from making a proper cut. Moreover, in some tools, and especially those in which the blade is not retractable, there are no means to properly hold the two halves together until the permanent attachment means are in place so that there may be misalignment of the blade.
In some utility knives the front end of the mouth is anchored, the other parts of the two halves are not anchored and must be held together by a screw. This requires the user to manually hold the two halves together until a screw is threaded through the two halves.
U.S. Pat. Nos. 3,872,591; 4,761,882; 4,240,202; 4,603,356; and 2,467,481 disclose a variety of utility knives in the prior art.